Pavement.



Patented July 24,1917'.

FIGLIA..

FIC-l1. 2.

PAVEMENT.

Specication of Letters Patent.

- Patented any ai, mit.

' Application filed January 24, 1917.- Serial No.'1`44,284.

To all/whom 'it may concerns Be it known that I, HENRY J. KAISER, `acitizen of the United States, residing at Everett, in the county ofSnohomish and State of Washingtonj have invented a new and useful'Improvement-in Pavements, of which the following is aspccification.

This invention relates to certain new and useful improvements in`pavements for streets and roads.

One of the important objects of the present invention is to so simplify'the construction of pavements as to reduce the cost of repairs tothegninimum.

Those experienced in the construction and Imaintenance of streets androads know that one of the most important factors connected therewith,which is emphasized more and more each succeeding year is that of costof maintenance, and 'it has/been demonstrated beyond question that thecost of i"epairs can only be reduced by improving the construction. y

The travel on streets and roads is increas` ing amazingly, bothin'volume and weight, and advanced engineering' methodsI are sought andemployed in the construction of crete with a thin layer of oil or othersuitpart of this specification, is shown the preferred embodiment of mypresent invention. Figure 1 is a vertical cross section on line :1e-m inFig. 2.

Fig. Q is a top View of 'a longitudinal fragment.

Fig. 3 is a vertical "cross section of expansion joint with angle ironsattached;

Same letters refer to similar parts throughout the several views.

In carrying out inyinventionl first preparc the foundation or what maybetermed the bed, to receive the 'concrete pavement, for with whatevercare the pavement may be laid it is very apt to be a failure unlessthe'foundation is good and dependable.A It is just as important a factorin road building as in any other work of construction, and while it istrue that concreteproperly made and laid has great inherentstrength itgives much better service and needs less attention if it be laid upon afirm, unyielding bed having a smooth, level surface.

Having Such a foundation I lay thereon, and thoroughly ram, a concretebase A varying in thickness from two to eightinches, of a rather leanmixture', bringing thetop to a smooth, evenfsurface by means of a float,trowel or the likef y No expansion jointsare placed in this primarylayer so that it may be denominated monolithic in character as it iscontinuous and unbroken.

After this primary layer of concrete has thoroughly set and hardenedthere is applied to the surface thereof a sheet of oil crude or heavy)or other suital'ilelubricant, B, especial care beingy exercised tosecure `a uniformly even distribution thereof over the entire surface. j

Upon this sheet of oil is placed a layer of paper of suitable thickness,C, to cover com pletely the sheet of oil, thereby preventing andseparating, during the process of construction, the secondary layer orwearing surface from direct contactwith the oil and primary labor. l

Immediately4 following the positioning` of the paper in the mannermentioned, the sec# ondary layer of concrete as the wearing surface, D,is superposed on the paper to a depth varying from two to eight inches;for this purpose a richer mixture may be used. The surface of thissecondary layer or wearing surface is finished smooth and level by meansof a float or the like. i

ln superposing the secondary layer or wearing surface as described,eXpansion joints, E, are placed equidistant, and in order to prevent theoints from rising and thereby allow the contiguous sections to` unite attheii` lower edges under the joint, there are attached to the lower edgeyof the expansion joint light weight angle-irons, G,

rat from five to twenty feet apart so that the concrete is deliveredonto the angle-irons at the base of the joint, thereby holding the jointin place andysecuring a water-tight joint. Y

When contiguous sections of the pavement unite beneath the expansionjoint, much of the benefit for which-the expansion joint is made is lostfor the pavement hasnot the same freedom of movement on the base uponwhich vit rests as it otherwise would, andhence the cau-se of cracksforming at expansion joints ata change in tem-l` perature. -f

The secondary layer or wearing surface may be reinforced by embeddingtherein f meshed iron or other suitable'material.

4 It will be noted that the expansion. joints provided f forin thesecondary layer. or

wearing surface are confined to the said layer whichr makes said layerindependent of the base on which itfrests so faras its sliding thereonis concerned, which freedom of movement is far .greater than can'vpossibly be provided in any pavement that consists of only one layer ofconcrete, and consequently the rcracking of pavement made according tothis invention isv reduced to the minimum.

. As the expansion joints under this invention extend through' thesecondary layer only, there is no opportunity for seepage of waterthrough'said joints to the roadbed and softening same which' is afrequent rcause of much injury to pavements as ordiyseep therethrough tothe roadbed for it is prevented first, by the paper, and second,

by the oil, and third, bythe primary layer of concretebeneath the oil.

Owing to the bottom course being of concrete it allows the topcoursetozbe lai-d more uniform by preventing the wet top concrete coursefrom `penetrating or leakiing into the l ibase, as 4inthe case of earthor other porous` subgra'de.-

I claim as my invention j 1. A pavement composed' of two inde- --pendentlayers of concrete, the primary layer-resting upon a suitable roadbedand a second layer superposedv on the primary layer witlra sheet of oilor other" suitable lubricant therebetween. l u

Q. A pavement composed of two independent layers of concrete, theprimary ayer resting upon assuitable roadbed, and

an upper secondary layer as a wearing surface, and a sheet of oiltherebetween.

3.. A pavement composed of twolfindeependentl layers of concrete,l theprimary layer resting upon a suitable .roadbedu and an upper secondarylayer as a Wearing surface,- and a sheet of oil and a layer of papertherebetween.

4. A pavement composed of two independent layers of concrete, the;primary v layer resting. upon a `suitable roadbed,. an upper secondarylayer' as a. wearing surface` with reinforcing means embedded therein,

and 'a sheet of oil and a layer ofpap'er therebetween. -i

5.`A pavement composed of two indeendent layers of concrete, theprimaryy ayer resting vupon a suitable roadbed,al 1y `Y upper secondarylayer as a wearingsurface," -asheet of. oil and ay layer of papertherebe-v tween,` and expansion joints extendingY from the; top ofl 'thewearing surface to. the vpaper j beneath.

6. A.y pavement' lcomprising 'a' suitable roadbed, a .primary layer ofconcrete com- 'pacted directly on said roadbe'd, a sheet of" oil appliedto the surface ofsaid primary layer, a'layer of paper of suitablethickness covering the sheet of'oil,`a'crust of concrete superposedon'the paper and having reinforcing means embedded therein, and eX-pnnsion joints extending yfl-om the ."top of tliefweariugsurface to the'5 paper beneath.

v7. A pavement composed of two independent .layers of .concriete, theprimary layer resting upon .asuitable roadbed," an .upper lsecondarylayer as a wearing surface,

a ,sheet-of oil vand a layer of paper t herebe tween, and@ expansionjointsextendmg from the top of the wearing surface to the paper beneathand provided vwith angle-irons at their loweredges. .j

8. A pavement comprising `a suitable sub-l grade,v a primary layer ofconcrete. supported directly upon said subgrade, v.a sheet of 1 oilapplied to the surface of said primary layer, a layer ofrelatively toughpaper of suitable thickness covering the sheet of oil,

a crust ofconcrete .superpowd on the paper as a wearing surface andexpansion jomts dividing said wearing sunface into sections'A adjacentto. each other, said `expansion ing surface to the paper bene'atli.

HENRY J. KAISER. I

joints `evtendinzgf from the topfof the Wear-

